The present invention relates generally to a slitter system wherein a web of paper or the like fed from a supply roll is trimmed and/or slit into two or more narrower webs. The invention was developed in connection with other improvements to the sheet cutting and stacking machines disclosed generally in applicants' prior U.S. Pat. Nos. 3,203,326 and 3,272,044, however, the invention herein is not limited to such an application. For instance, the slitting apparatus of the present invention could be used independently with a rewinding apparatus if desired.
The slitter units are mounted on a machine frame or the like for transverse movement across the web substantially as disclosed in the prior art. However, with the apparatus of the present invention, the slitter units can be positioned across the web far more readily and with greater accuracy than has been possible with prior art systems. Further, the apparatus of the present invention accomplishes its goals with less complicated equipment and with more automatic control than the systems of the prior art, to wit, only a single drive motor is required for the present invention.
The following prior U.S. patents are exemplary of the known slitter unit positioning systems:
U.s. pat. No. 1,118,831 PA1 U.s. pat. No. 3,176,566 (83-348) PA1 U.s. pat. No. 3,332,326 (93-58.2)
In U.S. Pat. No. 1,118,831, there is disclosed a slitting apparatus with a means for positioning the slitter knives with respect to one another. However, the apparatus disclosed therein requires a cumbersome manual adjustment which is time consuming and difficult to accomplish with a high degree of accuracy. U.S. Pat. No. 3,176,566 discloses a slitter system wherein the slitter units are positioned across the web by a remote means, but the individual slitter blades and slitter bands of each slitter unit are moved by separate, attached motors. Obviously the system disclosed therein would be subject to inconsistencies in the various drive motors, feedback units and actuation units, not to mention the increased costs and maintenance required for individual component motors. U.S. Pat. No. 3,332,326 discloses a system similar to that of the aforementioned patent except that a means is disclosed therein for simultaneously driving both of the elements of a slitter unit pair for gross displacement of the slitter units with respect to one another. However, the patented system still requires an individual motor for each slitter unit element and thus lacks the flexibility and simplicity of the apparatus disclosed for the present invention.